CBSE Class 12 Computer Science 2020 — Previous-Year Question Paper

Write the output of the following Python code: def Update(X=10): X += 15 print('X = ', X) X=20 Update() print('X = ', X)

Rewrite the following code in Python after removing all syntax error(s). Underline each correction done in the code. input('Enter a word',W) if W = 'Hello' print('Ok') else: print('Not Ok')

Find and write the output of the following Python code: def ChangeVal(M,N): for i in range(N): if M[i]%5 == 0: M[i] //= 5 if M[i]%3 == 0: M[i] //= 3 L=[25,8,75,12] ChangeVal(L,4) for i in L : print(i, end='#')

What possible output(s) are expected to be displayed on screen at the time of execution of the program from the following code? Also specify the minimum and maximum values that can be assigned to the variable End. import random Colours = ["VIOLET","INDIGO","BLUE","GREEN","YELLOW","ORANGE","RED"] End = randrange(2)+3 Begin = randrange(End)+1 for i in range(Begin,End): print(Colours[i],end="") (i) INDIGOBLUEGREEN (ii) VIOLETINDIGOBLUE (iii) BLUEGREENYELLOW (iv) GREENYELLOWORANGE

Differentiate between "w" and "r" file modes used in Python. Illustrate the difference using suitable examples.

Write a function Showwords() in Python to read the content of a text file 'NOTES.TXT' and display the entire content in capital letters. Example, if the file contains: "This is a test file" Then the function should display the output as: THIS IS A TEST FILE OR Write a function Showwords() in Python to read the content of a text file 'NOTES.TXT' and display only such lines of the file which have exactly 5 words in them. Example, if the file contains: This is a sample file. The file contains many sentences. But needs only sentences which have only 5 words. Then the function should display the output as: This is a sample file. The file contains many sentences :

Find and write the output of the following Python code: def Call(P=40,Q=20): P=P+Q Q=P-Q print(P,'@',Q) return P R=200 S=100 R=Call(R,S) print (R,'@',S) S=Call(S) print(R,'@',S)

Write a Recursive function in Python RecsumNat(N), to return the sum of the first N natural numbers. For example, if N is 10 then the function should return (1 + 2 + 3 + ... + 10 = 55). OR Write a Recursive function in Python Power(X,N), to return the result of X raised to the power N where X and N are non-negative integers. For example, if X is 5 and N is 3 then the function should return the result of (5)3 i.e. 125.

Write functions in Python for PushS(List) and for PopS(List) for performing Push and Pop operations with a stack of List containing integers. OR Write functions in Python for InsertQ(Names) and for RemoveQ(Names) for performing insertion and removal operations with a queue of List which contains names of students.

Computers connected by a network across different cities is an example of ______ .

______ is a network tool used to test the download and upload broadband speed.

A ______ is a networking device that connects computers in a network by using packet switching to receive, and forward data to the destination.

______ is a network tool used to determine the path packets taken from one IP address to another.

Write the full form of the following abbreviations: (i) POP (ii) VoIP (iii) NFC (iv) FTP

What is a secure communication? Differentiate between HTTP and HTTPS.

Helping Hands is an NGO with its head office at Mumbai and branches located at Delhi, Kolkata and Chennai. Their Head Office located at Delhi needs a communication network to be established between the head office and all the branch offices. The NGO has received a grant from the national government for setting up the network. The physical distances between the branch offices and the head office and the number of computers to be installed in each of these branch offices and the head office are given below. You, as a network expert, have to suggest the best possible solutions for the queries as raised by the NGO, as given in (i) to (iv). Distances between various locations in Kilometres: Mumbai H.O. to Delhi 1420 Mumbai H.O. to Kolkata 1640 Mumbai H.O. to Chennai 2710 Delhi to Kolkata 1430 Delhi to Chennai 1870 Chennai to Kolkata 1750 Number of computers installed at various locations are as follows: Mumbai H.O. 2500 Delhi branch 1200 Kolkata branch 1300 Chennai branch 1100 (i) Suggest by drawing the best cable layout for effective network connectivity of all the Branches and the Head Office for communicating data. (ii) Suggest the most suitable location to install the main server of this NGO to communicate data with all the offices. (iii) Write the name of the type of network out of the following, which will be formed by connecting all the computer systems across the network: (A) WAN (B) MAN (C) LAN (D) PAN (iv) Suggest the most suitable medium for connecting the computers installed across the network out of the following: (A) Optical fibre (B) Telephone wires (C) Radio waves (D) Ethernet cable

Which SQL command is used to add a new attribute in a table?

Which SQL aggregate function is used to count all records of a table?

Which clause is used with a SELECT command in SQL to display the records in ascending order of an attribute?

Write the full form of the following abbreviations: (i) DDL (ii) DML

Observe the following tables, EMPLOYEES and DEPARTMENT carefully and answer the questions that follow: TABLE : EMPLOYEES ENO ENAME DOJ DNO E1 NUSRAT 2001-11-21 D3 E2 KABIR 2005-10-25 D1 TABLE : DEPARTMENT DNO DNAME D1 ACCOUNTS D2 HR D3 ADMIN (i) What is the Degree of the table EMPLOYEES? What is the cardinality of the table DEPARTMENT? (ii) What is a Primary Key? Explain. OR Differentiate between Selection and Projection operations in context of a Relational Database. Also, illustrate the difference with one supporting example of each.

Write outputs for SQL queries (i) to (iii), which are based on the following tables, CUSTOMERS and PURCHASES: Table : CUSTOMERS CNO CNAME CITIES C1 SANYAM DELHI C2 SHRUTI DELHI C3 MEHER MUMBAI C4 SAKSHI CHENNAI C5 RITESH INDORE C6 RAHUL DELHI C7 AMEER CHENNAI C8 MINAKSHI BANGALORE C9 ANSHUL MUMBAI Table : PURCHASES SNO QTY PURDATE CNO S1 15 2018-12-25 C2 S2 10 2018-11-10 C1 S3 12 2018-11-10 C4 S4 7 2019-01-12 C7 S5 11 2019-02-12 C2 S6 10 2018-10-12 C6 S7 5 2019-05-09 C8 S8 20 2019-05-09 C3 S9 8 2018-05-09 C9 S10 15 2018-11-12 C5 S11 6 2018-08-04 C7 (i) SELECT COUNT(DISTINCT CITIES) FROM CUSTOMERS; (ii) SELECT MAX(PURDATE) FROM PURCHASES; (iii) SELECT CNAME, QTY, PURDATE FROM CUSTOMERS, PURCHASES WHERE CUSTOMERS.CNO = PURCHASES.CNO AND QTY IN (10,20);

Write SQL queries for (i) to (iv), which are based on the tables: CUSTOMERS and PURCHASES given in the question 4(g): (i) To display details of all CUSTOMERS whose CITIES are neither Delhi nor Mumbai. (ii) To display the CNAME and CITIES of all CUSTOMERS in ascending order of their CNAME. (iii) To display the number of CUSTOMERS along with their respective CITIES in each of the CITIES. (iv) To display details of all PURCHASES whose Quantity is more than 15.